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Title / Explain general microbiology, routine testing and control of microorganisms in a dairy processing operation
Level / 5 / Credits / 5
Purpose / This theory-based unit standard is for experienced people carrying out milk processing functions in a dairy processing operation.
People credited with this unit standard are able to describe the general morphological features, structure and reproduction of microorganisms important to the dairy processing industry; explain the relationship of microorganisms to the dairy processing function; factors affecting microbial growth and the use of these factors to control microbial growth in dairy products; explain the microbiological control of dairy products; microbiological testing of dairy products; and explain microbes of significance in a dairy processing operation.
Classification / Dairy ProcessingMilk Processing
Available grade / Achieved
Explanatory notes
Legislation relevant to this unit standard includes but is not limited to the Animal Products Act 1999, Health and Safety in Employment Act 1992, and Animal Products (Dairy) Regulations 2005.
Outcomes and evidence requirements
Outcome 1
Describe the general morphological features, structure and reproduction of microorganisms important to the dairy processing industry.
Evidence requirements
1.1Bacteria are described in terms of general morphological features and reproduction.
Rangegeneral morphological features and reproduction include but are not limited to – shape, size, cellular structure, motility, endospores, binary fission, bacterial growth curves.
1.2Fungi are described in terms of morphology and reproduction.
Rangeyeasts features include but are not limited to – size, cellular structure, budding, binary fission, ascospores;
moulds features include but are not limited to – size, mycelia structure, fragmentation, conidia, spores.
1.3Bacteriophages are described in terms of structure, reproduction, and control of growth.
Rangestructure, reproduction and control of growth includes but is not limited to – size, virion morphology, lytic life cycle, lysogenic life cycle, control of phage.
Outcome 2
Explain thefactors affecting microbial growth and the use of these factors to control microbial growth in dairy products.
Evidence requirements
2.1Nutrition of microbes is explained in terms of extracellular microbial enzymes and by-products of microbial growth.
Rangeby-products of microbial growth include but are not limited to – lipolysis, proteolysis, fermentation, toxin production.
2.2The effects of temperature on microbes are explained in terms of growth ranges, microbial classification by growth range, and effects of heat and cold on microbes in food.
Rangemicrobial classification by growth range includes but is not limited to – psychrophiles, psychrotrophs, mesophiles, thermophiles.
2.3The water activity scale, water activity growth ranges, and effect of osmotic pressure on microbes are explained in terms of effects on microbial growth.
2.4The pH ranges are explained in terms of effects on microbial growth.
2.5The classification of microbes is identified and explained in terms of oxygen requirement.
Rangerequirements include but are not limited to – aerobes, microaerophiles, anaerobes, facultative anaerobes.
Outcome 3
Explain the microbiological control of dairy products.
Evidence requirements
3.1The elimination of nutrients in dairy processing is explained in terms of process plant cleaning, and the design and maintenance of processing facilities.
3.2The use of temperature to control microbes is explained in terms of resistance of vegetative cells, spores, and thermophilic biofilms to heat and cold.
Rangeuse of temperature includes but is not limited to – pasteurisation, thermalisation, ultra-high temperature processing, refrigeration, freezing.
3.3The use of decreased water availability is explained in terms of sugared and dried foods.
Rangesugared and dried foods include but are not limited to – sweetened condensed milks, casein, powdered dairy products.
3.4The use of decreased pH to preserve dairy products is explained in terms of cultured products.
Rangecultured products include but are not limited to – cheese, fresh cultured products.
3.5The elimination of oxygen as a means to control microbial growth is explained in terms of vacuum packaging and canned products.
Rangevacuum packed and canned products include but are not limited to – cheese, canned, UHT products.
Outcome 4
Explain microbiological testing of dairy products.
Evidence requirements
4.1Classification of microbes is explained in terms of genera and species.
4.2Microbiological testing of dairy products is explained in terms of general laboratory enumeration and isolation techniques.
4.3Microbiological testing of the dairy process environment is explained in terms of general laboratory techniques.
Rangeprocess environments include but are not limited to – swabs, air, water.
Outcome 5
Explain microbes of significance in a dairy processing operation.
Evidence requirements
5.1Pathogenic bacteria of importance in dairy processing are explained in terms of growth characteristics, target populations, type of illness, infective dose, mortality rates, sources, and basic testing characteristics.
Rangepathogenic bacteria include but are not limited to – Salmonella species, Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, Bacillus cereus, Clostridium perfringens, Cronobacter sakazakii, Campylobacter jejuni, Yersinia enterocolitica.
5.2Spoilage organisms of importance to dairy processing are explained in terms of growth characteristics, types of spoilage, control methods, susceptible products, and basic testing characteristics.
Rangespoilage organisms include but are not limited to – yeasts and moulds, pseudomonas, thermodurics, sulphite reducing clostridia, spore-formers.
5.3Indicator organisms of importance to dairy processing are explained in terms of growth characteristics, control methods, and basic testing characteristics.
Rangeindicator organisms include but are not limited to – coliforms, enterobacteriaceae, enterococci, aerobic plate count, thermophiles.
5.4Beneficial microbes of importance to dairy processing are explained in terms of the effects of their growth on dairy products.
Rangebeneficial microbes include but are not limited to – starter bacteria, cheese moulds.
Planned review date / 31 December 2020Status information and last date for assessment for superseded versions
Process / Version / Date / Last Date for AssessmentRegistration / 1 / 18 June 2015 / N/A
Consent and Moderation Requirements (CMR) reference / 0022
This CMR can be accessed at
Please note
Providers must be granted consent to assess against standards (accredited) by NZQA, before they can report credits from assessment against unit standards or deliver courses of study leading to that assessment.
Industry Training Organisations must be granted consent to assess against standards by NZQA before they can register credits from assessment against unit standards.
Providers and Industry Training Organisations, which have been granted consent and which are assessing against unit standards must engage with the moderation system that applies to those standards.
Requirements for consent to assess and an outline of the moderation system that applies to this standard are outlined in the Consent and Moderation Requirements (CMRs). The CMR also includes useful information about special requirements for organisations wishing to develop education and training programmes, such as minimum qualifications for tutors and assessors, and special resource requirements.
Comments on this unit standard
Please contact the Primary Industry Training Organisation if you wish to suggest changes to the content of this unit standard.
Primary Industry Training OrganisationSSB Code 101558 / New Zealand Qualifications Authority 2018